Ағылшын тілінде оқу Өзгерту

Бөлісу құралы:


Query.SetFilter(Any, Text [, Any,...]) Method

Version: Available or changed with runtime version 1.0.

Sets a filter on a column of a query to limit the records in the resulting data set of a query.

Syntax

 Query.SetFilter(Column: Any, String: Text [, Value: Any,...])

Parameters

Query
 Type: Query
An instance of the Query data type.

Column
 Type: Any
The name of the column in the query that you want to filter. The name is defined by the column's Name Property.

String
 Type: Text
The filter expression. A valid expression consists of alphanumeric characters and one or more of the following operators: <, >, \, &, |, and =. You can use replacement fields (%1, %2, and so on) to insert values at run-time.

[Optional] Value
 Type: Any
Replacement values to insert in replacement fields in the filter expression. The data type of Value must match the data type of field that is referred to by the ColumnName.

Remarks

To apply filters to a dataset, the SetFilter method must be called before the Open, SaveAsXML, and SaveAsCSV methods, as shown in the following example. To remove filters from query, you call the Clear Method.

Query.SetFilter(Column1, String);  
Query.Open;  
Query.Read;  
Clear(Query);  

A call to the SetFilter method automatically closes a query dataset that is currently open. Therefore, the following code is unauthorized and will fail because there is no open dataset for the Read method to read.

Query.Open;  
Query.Read;  
Query.SetFilter(Column2, String);  
Query.Read;  

You can have multiple calls to the SetFilter method. If SetFilter method calls set filters on different columns, then the filters are combined and applied to the dataset. If consecutive SetFilter method calls set filters on the same column, then the last SetFilter method call is applied to the column.

In addition to the SetFilter method, you can apply filters to a query using the SetRange Method (Query) method, the FilterGroup method, and the DataItemTableFilter Property and ColumnFilter Property.

If the SetFilter method... then...
Sets a filter on the same field as the DataItemTableFilter property The two filters are joined into a resulting filter.
Sets a filter on the same field as the ColumnFilter property The SetFilter method overwrites the ColumnFilter property, so the filter that is set by the SetFilter method that is applied to the dataset.
Sets a filter on the same field as the SetRange method The method that is called last is applied to the dataset.
Sets a filter on a field that has global filters that are applied by the FilterGroup(1) method The filters of the SetFilter method are added to the global filters.

For example, a query has the following filters set on the Quantity column:

  • DataItemTableFilter property: Quantity=Filter(<100)

  • ColumnFilter property: Quantity=Filter(<>50)

Query.SetFilter ("Quantity", '>1') will result in a filter that is equivalent to: 1<Quantity <100.

Example

The following AL code example demonstrates how to use the SetFilter method on a query. The example code sets a filter on a query column, and then displays a message when the query is run that indicates the filter on the column.

This example requires that you create a query called Customer_SalesQuantity that has the following characteristics:

  • Links table 18, Customer with table 37, Sales Lines from the CRONUS International Ltd. demonstration database.

  • Includes columns for the Name and No. fields from the Customer table and the Quantity field from Sales Lines table.

var
  MyQuery: Query "Customer SalesQuantity";
  Text000: Label 'Customer name = %1, Quantity = %2';
begin
    // Sets a filter to display only sales quantities greater than 10.  
    MyQuery.SetFilter(Quantity, '>10');  
    // Sets a filter to display the columns with the value Selangorian Ltd. only.  
    MyQuery.SetFilter(NAME, 'Selangorian Ltd.');  
    // Runs the query.  
    MyQuery.Open;  
    // Reads each row in the dataset and displays message with column values.  
    // Stops reading when there are no more rows remaining in the dataset (Read is False).  
    while MyQuery.Read do  
    begin  
      Message(Text000, MyQuery.Name, MyQuery.Quantity);  
    end;   
    // Saves the resulting dataset as a CSV file.  
    MyQuery.SaveAsCSV('c:\temp\CustomerSales.csv');  
    // Closes the query.  
    Myquery.Close; 
end;

When the code is run, a message that resembles the following appears for each row in the dataset:

Customer name = Selangorian Ltd., Quantity = 30

Query Data Type
Get Started with AL
Developing Extensions